Cable probe devices are frequently used when a probe, for example a capacitive filling-level measuring device or a pressure sensor, has to be positioned in a location which is not readily accessible. An example of this is the introduction of a probe at a particular level in a tank or vessel. The cable serves to secure the probe. At the same time, the electrical supply and the transmission of information, especially of measurement signals, can pass via this connection between probe and housing.
In order for such cable probe devices to be suitable for industrial use, it is necessary to ensure that the cable and its fixing device withstand all process-induced stresses, in particular high tensile forces. Preferably, the fixing device also withstands, in addition, those tensile forces which result in the parting of the cable, for example tensile forces of several thousand newton.
Simplicity of handling, for example installation without special tools, is advantageous. Furthermore, in order to reduce any storage that may be necessary, provision is to made for the cable to be capable of being shortened by the customer to a length corresponding to requirements.
In the above mentioned commercially available probes, the cable passes between two clamping blocks which engage with one another via a toothing In assembly, the clamping blocks have to be placed against the cable and held there. The package comprising cable and clamping blocks is then introduced into a housing section which tapers in the direction away from the housing. The clamping blocks are likewise tapered in the direction away from the housing. Once the clamping blocks have been introduced sufficiently far into the housing section, the cable is firmly clamped by them and the housing section. The clamping blocks are moved in the housing section, in the direction away from the housing, by tensile forces now acting on the cable. As a result of the tapering of the section in this direction, the clamping is further tightened by this movement.
A disadvantage of such a cable probe device is that two clamping blocks are necessary)to secure the cable and cannot be fixedly connected to the cable, as it will otherwise no longer be possible for them to be pushed into each other via the toothing. As a result, the fixing device only engages when the clamping blocks have been introduced sufficiently far into the housing section. If this has not been done in advance, the clamping blocks do not bear tightly on the cable and the latter slips through the clamping blocks even under a low tensile stress.
The object of the invention is to provide a cable probe device which can be simply installed without special tools, in which the fixing of the cable takes place as a result of tensile forces acting on the cable, and in which the cable can be shortened by the customer to a length corresponding to requirements.
This object is achieved, according to the invention, in that the cable fixing device has a member having an axial, conical internal bore tapering in the direction away from the housing. In the axial, conical internal bore is arranged a cone tapering in the direction away from the housing. The cone tightly encloses the cable and can be displaced thereon only by an external force. The core has an axial cylindrical bore through which the cable is guided, and has cut-outs extending in the longitudinal direction of the cone and passing through the wall of the cone, as a result of which the cone can be compressed in the radial direction in a manner such that the internal diameter of the con e can be reduced.
According to one embodiment, the member is arranged in a section of the housing and rests on a sealing member, encompassing the cable, which sealing member in turn rests on a step, adjoining a cable exit aperture, of the section.
According to a further embodiment, an inner lateral surface of the cone is roughened. The inner lateral surface of the cone has in particular a structuring of saw-toothed grooves running around in an annular manner.
In an alternative embodiment, the cut-outs are arranged symmetrically in the cone.
In another alternative embodiment, each end surface of the cone is broken by at least one cut-out.
The cuts, in the yet another embodiment, each further take the form of a gap and a web extends between closely neighboring cut-outs.
In yet a further embodiment, the cut-outs are arranged in groups, one group comprising at least two rows of cut-outs arranged parallel to each other and parallel to the longitudinal axis of the cone, and a narrow wall strip existing between the rows.
In another alternative embodiment, the webs are each placed at the height of the center of the cut-out arranged extending respectively parallel thereto in the adjoining row.
In yet another embodiment, the cone consists of a rigid plastic, especially of a polyester, for example polybutyleneterephthalate, or a polyamide.